Process for making a flanged metal product having raised portions around its flange

ABSTRACT

A process for making a flanged metal product having one or more raised portions around its flange, such as an alternator rotor pole core, a transmission planetary gear, or the like, comprising first forming a semi-finished product having raised portions which are thicker, shorter and less steeply inclined with respect to the flange than the corresponding parts of the finished product by applying pressure by a punch directly to melted metal in a die cavity until the metal solidifies, and then forming the finished product by squeezing the semi-finished product into a die cavity having the same shape as the desired finished product to bend the raised portions inwardly at the lower ends, while simultaneously ironing the raised portions to thin and elongate them.

United States Patent Awano et a1. 1 1 Nov. 6, 1973 [54] PROCESS FOR MAKING A FLANGED 1,263,271 4/1918 Mossherg 29/527.5 X

METAL OD HAVING RAISED giigr hellmkml. "150118 a... PORTIONS AROUND FLANGE 1,555,285 9/1925 Hoey 164/120 [75] Inventors: Taikichi Awano; Yoshihiro Oishi, 1,612,373 12/1926 Jones 0 both of Nagoya Japan 1,956,907 5/1934 M11161 Ct a1. 164/120 3,106,002 /1963 Bauer 164/120 [73] Ass1gnee: Kahushiki Kaisha Toyota Chuo KenkyuSho Alchbken Japan Primary Examiner-Richard J. Herbst [22] Filed: May 7, 1971 Assistant Examiner-DC. Reiley I11 pp No: 141,334 Attorney-Berman, Davidson & Berman [57] ABSTRACT Foreign Application Priority Data M 12 1970 J /408 A process for making a flanged metal product having ay apan one or more raised portions around its flange, such as t 52 us. c1 29/598, 29/159 R, 29/527.5, gig 2 fga s s z i 29/607 29/1310. 18 164/76 164/D1G. 10 t" 6 P g 51 I t Cl B23 17/00 finished product having raised portions which are i 5 R thicker, shorter and less steeply inclined with respect to 1 g 4 5 the flange than the corresponding parts of the finished 76 product by applying pressure by a punch directly to melted metal in a die cavity until the metal solidifies,

and then forming the finished product by squeezing the [56] References Cited semi-finished product into a die cavity having the same UNITED STATES PATENTS shape as the desired finished product to bend the raised 1,772,215 8/1930 Grant 29/DIG. 10 portions inwardly at the lower ends, while simulta- 2,015,462 9/1935 Sachs 164/76 neously ironing the raised portions to thin and elongate 2,960,764 11/1960 Reichl 29 159 R them.

2,323,972 7/1943 Brauchler... 29/D1G. l8 1,494,410 5/1924 Bidle 29/159 R 14 Claims, 11 Drawing Figures 3,769,696 SHEET 10F 2 FIG-5.

INVENTORS O/SH/ ATTORNEYS.

PATENTEU NOV 6 I975 PROCESS FOR MAKING A FLANGED METAL PRODUCT HAVING RAISED PORTIONS AROUND ITS FLANGE BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to a proces for making a flanged metal product having raised portions around the flange and including a first step of producing a semi-finished product by liquid metal forging and a second step of plastically forming the semi-finished product into the ultimate desired shape of the finished product.

2. DESCRIPTION OF THE PRIOR ART Flanged metal products having raised portions at the periphery of their flanges, have been produced by cutting bars of metal with suitable cutting means, applying several forging steps to each cut bar to form the raised portions so as to gradually bringing the product to required shape, and finally trimming to obtain the finished product. The first conventional process has the drawbacks of requiring several process steps, necessitating large forming machines weighing several hundred to several thousand tons for each step, leaving a large amount of flash, and utilizing a high material product ratio involving waste of material Recently a new and second conventional process for the production of such metal products, as abovementioned, has been introduced, in which hydrostatic pressure is directly applied through a punch to melted meta] placed in a die cavity until solidification of the metal in the shapeof the finished product is obtained. Although this liquid metal forging process enables saving of a significant amount of time and decreases the material product ratio, it, too, has various drawbacks. A large number of defective products are made because of cold-shut, mis-run, and other faults. Furthermore, certain thinner parts of the die are deformeddue to high temperature of the melted metal and high pressure (-30 Kg/mm) even if the dies are made of heat resisting molybdenum. Therefore, the life of the die is short and limited to the making of approximately one hundred pieces.

SUMMARY OF THE INVENTION The process of this invention enables the efficient utilization of the advantages of the above-mentioned second conventional, liquid metal forging process, without any of its drawbacks. The inventive process consists of the steps of producing a semi-finished product having thicker, more outwardly inclined, and shorter fingers, or raised portions, on the flange than those of the desired finished product, and subsequently forming the finished product by application of pressure thereto to squeeze said semi-finished product into a die cavity of the same shape as the finished product, by bending the fingers inwardly and simultaneously ironing the fingers to make them thinner and longer.

In the first step of the process the cavity for the semifinished product is of such shape that the portions for forming the fingers, or raised portions, are inclined outwardly to a considerable degree so that the upper ends of said portions are located close to, or lower than the level of the melted metal. When melted metal of substantially the same weight as the finished product is poured into the die cavity, the cavity is completely filled with melted metal to the upper ends of the fingers and, therefore, during pouring of the melted metal and application of pressure, formation of cold-shut, or misrun, is prevented.

Since the cavity portions for forming the fingers are shaped sufficiently wider than the corresponding portions of the fingers in the finished product, only slight cooling at the level of the melted metal occurs and cold-shut, or mis-run, is totally, or almost totally prevented, even if the upper ends of said cavity portions are located a little higher than the level of the liquid metal. Furthermore, the much more outwardly inclined fingers of the semi-finished product being thicker and shorter require thicker and shorter protrusions in the upper die, or punch. This strengthens the die apparatus, reducing the deformation thereof due to high temperature and pressure, facilitating the provision of a cooling-water pipe therein, which further prevents deformation of the mould parts. The protruding portions of the upper die can be provided with rounded corners since the final forming of the product is carried out in the subsequent second step, and this fact contributes to preventing the deformation of the die.

In the second step of the invention process the mechanical strength of the fingers, or raised portions, of the product is improved since an ironing effect is applied thereto at the same time as the fingers are bent inwardly to the required angle of the finished product.

As thus briefly described, the process of the invention enables significant reduction of fabrication time and steps with comparison to the first-named conventional process, while obtaining finished products of excellent quality free from the drawbacks of the secondnamed conventional process involving liquid metal forging alone.

From the above it will be apparent that the primary object of the invention is to provide an improved process for producing a metal product having raised portions about its flange, which obviates the disadvantages of conventional processes, as briefly outlined above, and which yields products of excellent quality with a minimum number of steps.

Another object of the invention is to provide a process for making a metal product, having the abovedescribed characteristics, which produces an excellent yield and products having excellent mechanical strength.

A further object of the invention is to provide a process for making a metal product, having the abovedescribed characteristics, which obviates mis-run of the molten metal in a die cavity and, therefore,prevents formation of cold-shut in the product.

A still further object of the invention is to provide a process for producing metal products, having the above-described characteristics, which extends the life of the dies utilized in the process.

BRIEF DESCRIPTION OF THE DRAWINGS TI-Ie novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention, itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments, when read in connection with the accompanying drawings, wherein like reference characters indicate like parts throughout the several Figures, and in which:

FIG. 1 is a perspective view of an alternator rotor pole core exemplifying one finished product which can be made by the process of the invention;

FIG. 2 is a perspective view of a semi-finished alternator rotor pole core as produced in the first step of the present invention, and which is to be formed into the alternator rotor pole core shown in FIG. 1, as the finished product;

FIG. 3 is a central cross section of conventional liquid metal forging die apparatus for directly making the alternator rotor pole core of FIG. 1;

FIG. 4 is a central cross section of the dies used in the first step of the inventive process to make the semifinished alternator rotor pole core shown in FIG. 2;

FIG. 5 is a cross sectional view of the dies used in the second step of the inventive process to make the finished alternator rotor pole core of FIG. 1;

FIG. 6 is a perspective view partially cut away to reveal parts in section, of a planetary gear which may be made by the process according to the invention;

FIG. 7 is a cross section of the dies used in the first step of making a semi-finished planetary gear, preliminary to the gear of FIG. 6, in the first step of the inventive process;

FIG. 8 is a cross section of the dies used in the second step of the inventive process to form the finished transmission planetary gear illustrated in FIG. 6;

FIG. 9 is a perspective view, partially cut away to reveal parts in section, of another transmission planetary gear having internal gear teeth instead of external gear teeth;

FIG. 10 is a cross section of the dies used in the first step of the invention to provide a semi-finished transmission planetary gear, preliminary to the gear of FIG. 9; and

FIG. 11 is a cross section of the dies used in the second step of the inventive process to complete the transmission planetary gear illustrated in FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 is shown a finished automobile alternator rotor pole core 1 (hereinafter referred to as pole core), which is one type of flanged product having raised portions at its periphery suitable for making by the process of the present invention. The pole core includes a circular flange 11 having a boss 12, or hub in the center of its upper surface and a plurality of raised portions 13, or fingers, at the periphery of flange 11, each of said raised portions being tapered toward the end thereof, and said ends being located higher than the top surface of the boss 12.

Pole core 1 can be produced directly, by the second conventional process mentioned above, by forming in the dies illustrated in FIG. 3, which include a cavity of identical shape with the finished product 1. Cavity 20 is formed between a lower die 22 secured on the press bed 21 by bolts 24, and an upper die 23. Melted metal of substantially the same weight as the finished product is poured into the cavity and pressure is applied to the melted metal by punch 25, while the upper die is firmly pressed against the lower die, until the metal is solidified. The product is ejected by knock-out punch 26. This conventional process saves a significant amount of time and decreases the material product ratio, but it has several disadvantages. Melted metal is poured into the die cavity to the level of line a, FIG. 3, which crosses the tapered portions 27 of the cavity 20 corresponding to the cast fingers 13 of pole core 1, re sulting in cold-shut in the product, i.e., a flaw caused, by too rapid congealing in the mould. The melted metal in these thinner portions is rapidly cooled due to the tapered shape of the portions, interrupting flow of the molten metal and causing mis-run, i.e., a failure of the melted metal to fill the cavity completely. Furthermore, as previously stated, parts of the die such as corner portions having small radii, or reduced thickness, for example, the tapered portions 231 of the upper die 23, may be deformed after a relatively small number of products are produced.

The enumerated drawbacks of the liquid metal forging process and of the first conventional forging process are overcome by the present invention, as will be explained in detail with reference to the following examples.

EXAMPLE I This example explains the inventive process as applied to the manufacture of pole core 1, FIG. 1.

In the first step of the process, a semi-finished product 10, as illustrated in FIG. 2, is formed, Intermediate product 10 has fingers 131 which are thicker, shorter, and less steeply inclined with respect to the flange 111 than the fingers 13 of finished product 1, FIG. 1, and the outer ends of the fingers are lower rather than higher than the top surface of the boss 121, corresponding to boss 12 of the finished product.

The semi-finished pole core 10 is produced, for example, by dies shown in FIG. 4 which define a cavity 30 of the same shape as the semi-finished pole core. The dies include a bottom plate 32 for forming the bottom surface of core 10, a lower die 33 for forming the external surfaces of fingers 131, and an upper die 34 for forming the upper surface of pole core 10. A downwardly inclined surface 322 surrounds the flat circular die surface 321 of bottom plate 32 and serves to form the lower ends of the pole core fingers 131. An inclined surface 331 of the lower die 33 forms the outer inclined surfaces of fingers 131, and surface 341 having rounded protruding portions forms the upper surface and boss 121 of pole core 10. The surface 342 of the upper die 34 corresponds to the upper ends of the fingers 131 and is located approximately at, or below, the level of the liquid metal poured into the die cavity 30. The cavity portions 301, for forming the fingers 131, are wider and shorter than, but substantially identical in volume to the fingers 13 of the finished pole core 1. The cavity 30 has the same shape as that of the semifinished pole core 10. The bottom plate 32 and the lower die 33 are mutually fixed by bolts 372 and mounted on the press bed 31 by bolts 371 passing through the bottom plate 32.

Melted metal having substantially the same weight as that of the finished product, pole core 1, is poured into the cavity 30 through a bore in the upper die 34 for inserting the punch 35. Then, the punch 35 is lowered to apply hydrostatic pressure on the melted metal until it completey solidifies, thereby forming the semi-finished pole core 10 of the shape shown in FIG. 2. A knockout punch 36 is raised after solidification of the metal to eject the formed semi-finished product. The semifinished pole core 10 is free from detects. The ourwardly inclined fingers 131 having lower ends than the fingers 13 of core 1 enable complete filling of melted metal up to the top of the cavity portions 301 corresponding to the tops of fingers 131 and, therefore, prevent the formation of cold-shut, or mis-run, in said flngers. Since the final shaping of the product is achieved in a second step of the process, the protruding portions 341 of the upper die are made shorter and with more rounded corners than the corresponding portions 231 of the FIG. 3 dies, enabling the incorporation of a cooling-water pipe (not shown) in the upper die 34. These factors give the upper die more resistance to high temperature and high pressure, and prevent its deformation, particularly at the protruding portions, even after repeated use.

In the second step of the inventive process the semifinished pole core is subjected to plastic deformation by applying pressure thereto to squeeze said semifinished product into in a die cavity of the identical shape with the desired finished pole core 1. The cavity is provided in dies composed, for example, as shown in FIG. 5, of a support 42 fixed on a press bed 41 by bolts 421, a die 43 mounted on said support by bolts 431, a guide 45 for supporting the bottom of the semi-finished pole core, and a punch 44 for pressing the pole core from above. The surface 422 and 432 of support 42 and die 43 are directed vertically to form the external surfaces of the fingers 13 in the finished pole core 1. The surface 451 of the guide 45 has a shape identical with the bottom surface of the semi-finished pole core, while the surface 441 of punch 44 is shaped like the upper surface of the finished pole core 1. The described die surfaces define finger-making portions which are thinner and longer than those of the semi-finished pole core whose external surfaces are perpendicular to the flange face 111, rather than inclined. Die 43 is provided at the upper opening thereof with a conical face 433 whose angle of inclination is identical with, or larger than, the angle of the fingers 131 of the semi-finished pole core, and this face constitutes a guide for inserting the pole core 10 into thedie-cavity.

In the secondstep of the present process, the semifinished pole core 10 is placed on the conical face 433 of die 43 and pressed downwardly by the punch 44 to squeeze the product into the die cavity while the guide 45 is positioned to support the pole core. Thus, the core 10 is subjected to forming during which the fingers 131 are bent inwardly and ironed between the surface 432 of the die and the surface 441 of the punch, where'by't'he fingers are elongated to till the cavity completely and to form fingers 13 of the finished pole core. At the same time, the rounded corners on the semifinished pole core between the side face of boss 121 and the upper face of flange 111, and between the flange upper face and the internal faces of the fingers 131, are subject to plastic deformation by the surface 441 of punch 44 so as to achieve the desired shape having reduced roundness, A limited amount of flash formed on the semi-finished core 10 is removed by the transition area 434 between the inclined surface 433 and vertical surface 432 of the die 43 when the semifinished core is pressed into the die cavity. The forming of the second step, as described, can be carried out either as hot-forming, or cold-forming, depending upon the work material. Upon completion of the forming of pole core 10 along the surface 432 and 441 of the die 43 and the punch 44, the finished pole core 1 is taken out of the die cavity by lowering the punch 44 and the guide 45.

Fingers 13 in the pole core thus obtained are free from defects due to cold-shut, or mis-run, and have improved mechanical strength due to the ironing applied thereto. With the described process and apparatus the surface of the upper die used in the first step is not deformed, and this die has a longer life. For example, a die made of steel (SKD 61) lasted thirty times longer than the corresponding die 23 of the second conventional liquid metal forging process. The process according to the invention produces items of exact desired shape due to the use of the second and final forming step, even if the die used in the first step shows some deformation. Furthermore, the inventive process, in comparison with the first-mentioned conventional plastic forming process, not only reduces the process time significantly, but also dispenses with the need for many forming machines. In the inventive process, forming with lower capacity machines is possible in the first step, and also in the second step when this is carried out in hot condition.

EXAMPLE 2 This example explains the invention as applied to the making of a transmission planetary gear having gear teeth on the external surface of a rim thereof, such as for a helicopter. A transmission planetary gear 5 of this type is shown in FIG. 6 as comprising a flange 51 having a tubular cylindrical boss 52 at the center of its upper surface, an annular rim 53 extending perpendicular from the periphery of the flange to a level higher than said boss, and gear teeth 54 on the external peripheral surface of the rim 53.

The dies shown in FIG. 7 are used in the first step of the inventive process and include a bottom plate 62 fixed on the press bed 61. Plate 62 has a central flat area on its upper surface labeled 621 surrounded by annular downwardly inclined areas 622. A lower die 63 is fixed on the bottom plate 62 and has gear teeth forming surface 631 which is more outwardly inclined than the corresponding rim 53 and teeth 54 of the finished gear 5. The die surface 631 has a series of projections and recesses, corresponding to the gear teeth of the semi-finished transmission gear to be obtained inthe first step. These projections are shorter, thicker and have a greater radius at the edges than the corresponding grooves between the teeth 54 of the intended finish gear 5. It is possible to form those projections in linear shape of constant width with recesses therebetween which widen upwardly, or to form said recesses of constant width with projections therebetween which widen upwardly. The upper die 64 seats on the lower die 63 and has a surface 641 for forming the upper surface of the gear flange and the internal surface of the rim 53, and a surface 642 for forming the upper surface of the rim. The surface 641 is outwardly inclined and has rounded corners at its extremities. Consequently, the semi-finished gear, formed in the die cavity defined by the surfaces 621, 631and 641 of the bottom plate 62, the lower die 63 and the upper die 64, respectively, is provided with a rim more outwardly inclined, thicker as a whole, and particularly thicker at the lower end thereof at the periphery of the flange, and with thicker and shorter gear teeth on the external surface, as compared with the shape of the finished gear 5. The surface 642 of the upper die 64 is positioned lower than the upper surface of the boss 52 on the finished gear 5.

In the first step of the process, melted metal of sub stantially the same weight as the finished product (in calculating the weight the boss is considered to be a solid rather than hollow cylinder) is poured through the bore of the upper die into said cavity, and the punch 65 is inserted and lowered through the same bore while the upper die is pressed downwardly to form the semifinished gear. During this step the melted metal completely fills the cavity portion for forming the rim, thereby preventing the formation of cold-shut, or misrun, as in Example 1. The semi-finished gear is removed from the dies by the knock-out punch 66 and transferred to the dies, shown in FIG. 8, for performing the second step of the inventive process.

The dies of FIG. 8 define a cavity of identical shape as the finished gear 5. The surfaces 722, 732 and 751 of a support 72 fixed on the press bed 71, a die 73 and a punch 75, respectively, form part of the die cavity. A conical face 733 on die 73, as in Example 1, receives and guides the semi-finished gear into the die cavity and pressure is applied to the gear by the punch 75 under hot, or cold condition to forge the gear while the guide 76 with flat upper surface 741 is positioned to support the semi-finished gear. Thus, the rim of the semi-finished gear is inwardly bent and simultaneously ironed between the surfaces 732 and 751 causing the rim to extend upwardly and fill the space defined by the surfaces of the die and punch, thus obtaining the desired shape of the final product, gear 5. Simultaneously, the gear teeth on the external surface of the rim are subjected to plastic deformation according to the shape of the surface 732 of die 73 when the semi-finished gear is lowered into the die cavity. The final finished gear is taken out of the bottom of the die assembly by lowering guide 76, and the center hole in boss 52 is formed by piercing, or drilling to yield a finished gear 5, FIG. 6.

EXAMPLE 3 The inventive process can be utilized not only for the production of gears having external gear teeth on their rims as shown in FIG. 6, and described in Example 2, but also for making gears having gear teeth on the internal surface of their rims as, for example, shown in FIG. 9. The transmission planetary gear 8, FIG. 9, comprises a flange 81 having a boss 82 at the center of its underside and an upstanding rim 83 on the upper side peripherally of the flange, the gear teeth 84 being on the internal surface of rim 83.

In the first step, a semi-finished gear is formed in cavity 90 of the die assembly shown in FIG. 10, This includes a lower die 92 having an annular flat surface 923 containing bore 922 for forming the central boss 82 and also for insertion of a knock-out punch 95, and an annular inclined surface 924 surrounding surface 923 and downwardly inclined toward the periphery of the die. Seated on the lower die 92 is a die 92' having outwardly inclined surface 921 surrounding a portion of surface 924 for forming the external peripheral surface of the semi-finished gear rim. An upper die 93 seats on die 92' and has a surface 931 for forming the upper surface of the rim. The punch 94, inserted in the center bore of upper die 93, applies pressure to melted metal in the die cavity 90 and has a surface composed of central flat area 941 and surrounding upwardly and outwardly inclined area 942 provided with shorter and thicker teeth than those of the finished gear product.

Thus, the shape of the semi-finished gear is defined by the surfaces of saidlower die, upper die and punch, as described above.

The semi-finished gear is obtained by pouring melted metal of substantially the same weight as the finished product through the center bore of the upper die 93, while the upper surface 951 of the knock-out punch is positioned at the same level as the surface 923 of the lower die 92 (line 6 in FIG. 10). The liquid 'metal reaches the level of line 0 to fill the cavity completely to the level of surface 931 of the upper die 93. Successively, the punch 94 is lowered to apply pressure on the melted metal while the upper die is pressed downward, and said knock-out punch 95 is lowered also so as to retract the surface 951 to the required height of the boss 82 of the gear 8. The melted metal is solidified under these conditions to obtain the semi-finished gear, which has a rim more outwardly inclined and thicker and shorter than the finished gear product, and which rim is further provided with thicker and shorter teeth along the internal periphery of the rim than the teeth 84 of the finished gear.

In the second step of the inventive process, the semifinished gear thus obtained in inserted into the die cavity having the identical shape as required for the finished gear in the die assembly shown in FIG. 11 to forge the finished product. This assembly includes a support 102, a die 103 and a punch 104 provided with gear teeth forming surface 1041 at the external periphery of its lower end. The semi-finished gear is placed on the conical face 1032 of the die 103 and plastically formed by applying pressure thereto with punch 104, while the guide 105 with flat upper surface 105] is positioned to support the semi-finished product. Thus, the rim of the semi-finished gear is bent inwardly and ironed between the surface 1031 of die 103 and the gear teeth forming surface 1041 of the punch 104, whereby the rim is extended upwardly and simultaneously gear teeth of desired shape and size are formed to realize the finished gear 8, FIG. 9. In this example also, the inventive process yields products free from any defects and extends the life of the dies.

The invention is not limited to the manufacture of pole'cores, or transmission planetary gears as described above, but can be applied to the forming of other metal products of somewhat similar shape.

Although certain specific embodiments of the invention have been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not intended to be restricted to the exact showing of the drawings and description thereof, but is considered to include reasonable and obvious equivalents.

We claim:

1. A process for producing a flanged metal product having a raised portion extending from its flange,comprising the steps of first forming a semi-finished product in which said raised portion is thicker, shorter and less steeply inclined with respect to said flange than is the raised portion of the finished product by pouring melted metal of substantially the same weight as that of the finished product into a suitably-shaped first die cavity, and applying pressure by a punch directly to said melted metal until it solidifies, removing said semifinished product from said first die cavity, and forming the finished product by applying pressure to said semifinished product to squeeze it into a second die cavity having the same shape as that of the desired finished product so as to bend the raised portion inwardly at the lower end thereof and simultaneously iron said raised portion into a thinner and upwardly longer shape.

2. A process according to claim 1, wherein said first die cavity is formed in a die assembly including an upper die having a rounded corner at a portion corresponding to the intersection of the upper surface of the flange and the internal surface of the raised portion of the semi-finished product, and a bore is provided in said upper die for insertion of said punch to apply pressure to the melted metal.

3. A process according to Claim 5, wherein said second die cavity is defined by die surfaces corresponding in shape to the bottom surface of the flange and the external surface of the raised portion of the finished product, and said squeezing pressure is applied to the semifinished product by a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the raised portion of the finished product.

4. A process according to claim 3, wherein said step of forming the finished product is a hot forming step.

5. A process according to claim 3, wherein said step of forming the finished product is a cold forming step.

6. A process according to claim 1 for producing a flanged alternator rotor pole core having a plurality of upstanding fingers around its flange, wherein said first die cavity has portions for forming said fingers thicker, shorter and less steeply inclined with respect to the flange of the alternator rotor pole core than the corresponding fingers of the finished pole core, wherein the semi-finished product is squeezed into said second die cavity having die surfaces of the same shape as the bottom surface of the flange and the external surfaces of the fingers of the finished alternator rotor pole core, and wherein said squeezing pressure is applied to the semi-finished pole core by a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the fingers of the finished pole core, thereby to bend the fingers of the semifinished core at their lower ends and simultaneously iron said fingers into thinner and upwardly longer shapes.

7. A process according to claim 6, wherein the melted metal is poured through a bore of an upper die forming part of said first cavity, the melted metal level in said bore being above the cavity portions which form the upper ends of said fingers.

8. A process according to claim 1 wherein said flanged metal product has a boss in the center part of said flange, and the portion of the melted metal for forming said boss is directly pressed by said punch.

9. A process according to claim 1 for producing a flanged transmission planetary gear having a cylindrical rim perpendicularly raised around its flange and gear teeth longitudinally disposed on one of the surfaces of said rim, wherein said first die cavity has a portion for forming the rim of the gear which is thicker, shorter and less steeply inclined with respect to the flange of the gear than the corresponding parts of the finished transmission planetary gear, the said die cavity having projections and recesses which form gear teeth, wherein said second die cavity has the same shape as the bottom surface of the flange and the external surface of the rim of the finished transmission planetary gear, and said squeezing pressure is applied to the semifinished transmission planetary gear by means of a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the rim of the finished transmission planetary gear, thereby bending the rim of the semi-finished transmission planetary gear at the lower end thereof and simultaneously ironing the same and said gear teeth into thinner and upwardly longer shapes.

10. A process according to claim 9, wherein said first die cavity projections and recesses for forming the gear teeth are so positioned on a die forming part of a die cavity assembly as to form said gear teeth on the external surface of the rim of the transmission planetary gear.

11. A process according to claim 9, wherein said first die cavity projections and recesses for forming the gear teeth of the transmission planetary gear are so positioned on a die forming part of a-die cavity assembly as to form said gear teeth on the internal surface of the rim of the transmission.

12. A process according to claim 9, wherein a semifinished transmission gear is formed in said first step having shorter gear teeth than those of the finished transmission gear, and pressure is applied thereto by means of a punch to plastically form said gear teeth into desired shape.

13. A process according to claim 9, wherein a semifinished planetary gear is formed having a rim which is thicker at the lower end than at the upper end, and pressure is applied to said semi-finished planetary gear by a punch to plastically form said rim into a shape having uniform thickness.

14. A process according to claim 9 wherein the melted metal poured through a bore of an upper die forming part of said first die cavity, the melted metal level in said bore being above the die cavity portions which form the upper edge of said rim of the transmission planetary gear.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,769,696 D t d Nov. 6, 1973 Inventofls) TAIKICHI AWANO, E T AL.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 9, line 13, delete- "Claim 5" and insert '-Claim l- Signed and sealed this 16th day of April 197A.

(SEAL) Attest:

EDWARD I I.I*LEIGHER,JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents go-mo (o-s9) UlCOMM-DC 00370-96.

. I... mill-III IIIIII II. I I" NO-m 

1. A process for producing a flanged metal product having a raised portion extending from its flange,comprising the steps of first forming a semi-finished product in which said raised portion is thicker, shorter and less steeply inclined with respect to said flange than is the raised portion of the finished product by pouring melted metal of substantially the same weight as that of the finished product into a suitably-shaped first die cavity, and applying pressure by a punch directly to said melted metal until it solidifies, removing said semi-finished product from said first die cavity, and forming the finished product by applying pressure to said semi-finished product to squeeze it into a second die cavity having the same shape as that of the desired finished product so as to bend the raised portion inwardly at the lower end thereof and simultaneously iron said raised portion into a thinner and upwardly longer shape.
 2. A process according to claim 1, wherein said first die cavity is formed in a die assembly including an upper die having a rounded corner at a portion corresponding to the intersection of the upper surface of the flange and the internal surface of the raised portion of the semi-finished product, and a bore is provided in said upper die for insertion of said punch to apply pressure to the melted metal.
 3. A process according to Claim 5, wherein said second die cavity is defined by die surfaces corresponding in shape to the bottom surface of the flange and the external surface of the raised portion of the finished product, and said squeezing pressure is applied to the semi-finished product by a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the raised portion of the finished product.
 4. A process according to claim 3, wherein said step of forming the finished product is a hot forming step.
 5. A process according to claim 3, wherein said step of forming the finished product is a cold forming step.
 6. A process according to claim 1 for producing a flanged alternator rotor pole core having a plurality of upstanding fingers around its flange, wherein said first die cavity has portions for forming said fingers thicker, shorter and less steeply inclined with respect to the flange of the alternator rotor pole core than the corresponding fingers of the finished pole core, wherein the semi-finished product is squeezed into said second die cavity having die surfaces of the same shape as the bottom surface of the flange and the external surfaces of the fingers of the finished alternator rotor pole core, and wherein said squeezing pressure is applied to the semi-finished pole core by a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the fingers of the finished pole core, thereby to bend the fingers of the semi-finished core at their lower ends and simultaneously iron said fingers into thinner and upwardly longer shapes.
 7. A process according to claim 6, wherein the melted metal is poured through a bore of an upper die forming part of said first cavity, the melted metal level in said bore being above the cavity portions which form the upper ends of said fingers.
 8. A process according to claim 1 wherein said flanged metal product has a boss in the center part of said flange, and the portion of the melted metal for forming said boss is directly pressed by said punch.
 9. A process according to claim 1 for producing a flanged transmission planetary gear having a cylindrical rim perpendicularly raised around its flange and gear teeth longitudinally disposed on one of the surfaces of said rim, wherein Said first die cavity has a portion for forming the rim of the gear which is thicker, shorter and less steeply inclined with respect to the flange of the gear than the corresponding parts of the finished transmission planetary gear, the said die cavity having projections and recesses which form gear teeth, wherein said second die cavity has the same shape as the bottom surface of the flange and the external surface of the rim of the finished transmission planetary gear, and said squeezing pressure is applied to the semi-finished transmission planetary gear by means of a punch having identical surfaces with the upper surface of the flange and the internal and upper end surfaces of the rim of the finished transmission planetary gear, thereby bending the rim of the semi-finished transmission planetary gear at the lower end thereof and simultaneously ironing the same and said gear teeth into thinner and upwardly longer shapes.
 10. A process according to claim 9, wherein said first die cavity projections and recesses for forming the gear teeth are so positioned on a die forming part of a die cavity assembly as to form said gear teeth on the external surface of the rim of the transmission planetary gear.
 11. A process according to claim 9, wherein said first die cavity projections and recesses for forming the gear teeth of the transmission planetary gear are so positioned on a die forming part of a die cavity assembly as to form said gear teeth on the internal surface of the rim of the transmission.
 12. A process according to claim 9, wherein a semi-finished transmission gear is formed in said first step having shorter gear teeth than those of the finished transmission gear, and pressure is applied thereto by means of a punch to plastically form said gear teeth into desired shape.
 13. A process according to claim 9, wherein a semi-finished planetary gear is formed having a rim which is thicker at the lower end than at the upper end, and pressure is applied to said semi-finished planetary gear by a punch to plastically form said rim into a shape having uniform thickness.
 14. A process according to claim 9 wherein the melted metal poured through a bore of an upper die forming part of said first die cavity, the melted metal level in said bore being above the die cavity portions which form the upper edge of said rim of the transmission planetary gear. 